Measuring device



June 6, 1944. J. yWHQL-:maxim MEASURING DEVICE Filed sept. 9, 1941 2Sheets-Sheet 1v ATTO RNEYS' June 6, 1944.` J. VERDRBER 2,350,432

` ,MEASURING DEVICE Filed sept'. 9,'. 1941 2 sheets-sheet 2v Flag]INVENTOR. 1;

Joss-:PH VERDERBER FIGB.'

Patented June 6, 1944 UNITED STATES PATENT OFFICE 2,350,432 MEASURINGnEvioE Joseph Vcrderber, Cleveland, Ohio slmiiation. september 9, 1941,serial No. 410,185

(C1. sra-172) 3 Claims.

This invention relates, generally, to a measuring device and hasreference, more particularly, to a device for accurately measuring theamount of movement between two relatively movable elements.

In my patent for Machine tool, No. Re. 21,795 dated May 6, 1941, I havedisclosed means for measuring the amount of movement between tworelatively movable elements, but such means require adjustment orsetting before each movementv to be measured has occurredand anotheradjustment after such movement has occurred. This is true, particularly,if such movement is for a relatively great distance, such as, forinstance, one-half of an inch or more. However, where the amount ofmovement between two relatively movable elements is slight, the amountof such movement can be accurately determined with but one adjustment ofsuch means, the adjustment taking place before the movement oc-` curs.This necessity for frequent adjustment, always before and almostl alwaysafter movement, has created a Want for a device as above set forth whichis constantly in adjustment and which does not require adjustment beforenor after movement between two relatively movable elements has occurredin order to indicate the precise amount of such movement,notwithstanding movement in an `amount far in excess of that above setforth. Thus, one of the cardinal ob-l jects of this invention has beento provide a device which will quickly and accurately measure very largeamounts of movement between two relatively movable elements without thenecessity of frequent adjustment or settings.

The disclosure of the above set forth patent includes Very accuratelyspaced abutments, the maintenance of the original accuracy of thespacing of the working faces of which might be questioned aftercontinuedand long enduring use. Said disclosure also includes a dialindicator, the limitations and maintenance of the accuracy of which issubject to certain objections if the same undergoes use other than as alaboratory instrument. Another of the objects of this invention has beento provide a device of the character identified above in whichthelimitations heretofore in this paragraph set forth are eliminated ltoa substantial degree.

The abutments of said patent are engaged by a member and all theintergaging surfaces are exposed and consequently subject to attack byand are apt to adhere to particles of dust, grit, and other foreignmatter which immediately and vadversely affect the accuracy of themeasurevenientlyl located.

- ment and which, if suffered to endure, have a permanent deterioratingeffect on such surfaces. Another v of the objects of this invention haslbeen tok provide a device by virtue of which such effects of dust,dirt, grit, and theV like are eliminated.

I have found that meansl constructed in accordance with myY said patentis somewhat bulky and presents certain objectionable protuberances,which, at times, unduly interfere with free movement of the operatorm Afurther object of this invention has been to provide a measuring deviceof the kind specified which is compact and which is free fromobjectionable projection.

Another of the objects of this invention is to provide a device whichwill very accurately measure both minute and great amounts of movementbetween two relatively movable elements and which will magnify suchmovement without the employment of a multiplicity of mechanical levers.

As has been above indicated and as can be more clearly ascertained by astudy of said y patent, the functioning of means constructed inaccordance therewith is dependent to some extent upon the operatorsability to feel very accurately the proper adjustment of a micrometer-afactor dependent upon the human element of feel which is developed to asuitable degree only by a highly skilled operator. One of the principalfeatures of the present invention is to eliminate the human element offeel.

In order to insure measuring means constructed in accordance with saidpatent against unintentional contact and thus preserve its accuracy, ithas been found desirable to locate the same in places which are more orless inconvenient. Thus, another object of this invention has been toprovide a device as described which is-not vulnerable to said contactsand, consequently, which can with increased safety be more con- Fuitherobjects of this invention have been to provide a measuring device whichis mechanically simple, not subject toreadily becoming out of adjustmentand the parts of which can be replaced without the use of speciallyprepared installation tools.

To the accomplishment of the foregoing and related ends, said invention,then, consists of the means hereinafter described and particularlypointed out in the claims; the annexed drawings and the followingdescription setting forth in detail certain structure embodying theinvention, such disclosed elements constituting, however,

connected to an element I 2.' vorthe inember III` may ber taken to beone of the relatively. movable elelnfients'.` The connection be.-

but one of various structuralforms in which the principle of theinvention may 'be used.

In said annexed drawings- Fig. l is a cross section of a device havingincorporated therein the principal features of this invention and istaken on the line I-I of Fig. 2;

Fig. 2 is a View partially in section and partially in elevation takenfrom the top of Fig. 1; and

Fig. 3 is a diagrammatic view of a device having incorporated thereinthemain features of a modification ofv this invention.

Briefly, although not necessarily condensed to the extreme, Vmy presentinvention comprisesa straight line presented by one of two relativelymovable elements, the other of such two relatively movable elementscarrying a roller which v*rolls along such line. The amount ofrotationof said.

elements are maintained free of lubricant so that movement, large orsmall and slow or rapid, of the element I2 with respect to the elementI8 will be extremely accurately reflected and equal to the length of thecircumference of the roller which has rolled along the bar.

yIn order to further make certain the accuracy of the circumferentialtravel of the roller along the bar as a true measure of the amount ofmovementbetv'veen the'relatively movable elements I2 and I8,'the rolleris mounted as frictionlessly as possible, such as by means of rollerbearings 26 and 2l carried by bosses of the cover and the housingrespectively. Further, the bar roller from any preselected zero point,assuch roller rolls along the straight edge, being a simple function ordirect indication ofthe amount that fone of s'aidfele'rnents hasmovedvwith respect tol `the other oflsaid elementsf." i

,'Withreferencenow to jsa'iddrawings,` and more speciflcallyjtoFigs, 1and 2 thereof, the said straight edgecan be taken to be any onev of anninfinitely large number of lines comprising'a AIlat surface. I0 of anelongated member I I, preferably barlofjrectangular cross-section, whichis Either the latter tween the member I I Yand the element IZTis suchthat no relative movement .therebetween isper- Ymitted along the lengthofthe former. Thus, this connection may bepivotal about an `axis,parallel to said surface and perpendicular to Fig. 2, or it may be onewhich permits limited Vmovement of thebar perpendicular to said surface.Thus, as is seen -in Fig. 2, the element I2 is provided with a recessI2a. wider than the bar II, and adjacent to the bottom of said recessthere isa ledge I2c along `the side face of the recess.V rThe bottom ofthe bar is provided with aprojection- I4 the upper face o f which rides-against the'lower face ofthe ledge. Of course, I a combinationlofbothtypes of connections may beused. This ,bar is of considerable lengthand, `asis seen in Fig. 2, projects through a frame or housing,the'body,. I 6, of which, by suitable means `such asv ears vI'I, andbolts, is rigidly and immovablylcarried by an element I8. Either thehousing I6 or the element I8 may be taken to be the other of therelatively movable elements.

VIn` order to particularly prevent the entrance fofdust,dirt, gritandther foreignl matter into the Ahousing and in order to keep theentire bar I I clean and free from lubricant, the openings of theihousing'through which the bar projects are each providedwithvwipingmeansk 2l), vit being lnoted that the said openings are of dimensionsgreater than the transverse cross-sectionaly dimension of thebar so asto permit the use of A roller is supported at one end by the engages`the surface I Il.y I

f Thesurface l0 and the periphery or circurnferentialsurface oftheroller are both chromium platedandnished extremely fine so as toeliminate all variation'in excess of .000003 to .000004A Vof an inch,thusA insuring substantially continu-A ous line contact between suchsurfaces.' These Vbosses of the housing. Each ofthese fingers issurrounded by a spring 34 the ends of which engage the bushings so as tourge the disc toward the bar.V To further insure maximum contact betweenthe bar and the roller, suitable bar locating and auxiliary wiping means36 are provided and are supported by the housing.

Suitably secured, as by welding or by other means, tothe shaft of theroller 25 is a small at disc 40 which, by means of rivets or the like,has rigidly secured'thereto a flat annular plate 4I. Thus, the roller 25and plate 4I are rigidly interconnected and angular motion of the rolleran exact and precise measurement of the angu- -lar movement lof theroller. This plate is considerably larger in diameter'than is the roller25 and I have 'found it vconvenient to make the ratio of these diametersve to one so that, for each unitof circumferential movement of theroller 25, there will be five units of circumferenti'al movement of thedisc 4I and the rst multiplica'tionk or,magnif 1cation of movementbetween the elements. I2'and I8 is accomplished.

I prefer to accomplish'v further multiplication or magnification of suchmovement by means of light, preferably fluorescent, provided by a sourceof light A and alens 46. As is seen in Fig. 2, the outeredge of theplate 4I projects between the source of light and the lens and isprovided with suitable indicia 49 so, that the rays of light,

concentrated and directed by the light reflector 5|, encounter theindicia andpresent an .image to the lens 46. This image is magnified anydesirable number of times, such as nine, and is visibleA on `the lens'remote side of a screen 53 Awhich isV in the nature of a suitablyprepared glass plate which is supported by a casing 54, the

latter presenting a dark chamber interconnecting and spacing the' screenfrom the lens. f For focusing purposes the lens is movable between thesource oflight and the screen, and is threaded 'as vat 55 to either thehousing I6 or the'casing 54, the latter being suitably secured asbymeans of bolts 51 to the housing. v 4

For maintaining the annular glass screen in position, I havevprovidedthe' casing 54 with an interior ange 65 against the upper surface ofwhich rests the screen which isY held in place by an exteriorly threadednut 6I, there being a gasket 62 interposed between such screen and nut.

`If desired, this nut may be provided with an upwardly extending shieldfor shielding out light from exterior sources so that the screen may bebetter observed bythe workman.

For turning the sourceoi light on and o', I prefer to locate a switch,indicated generally by the reference character 65, in the immediatevicinity of the screen. Thus an angular ring 65 surrounds the upperportion of the casing 54 and presents electrical terminals 61 whichcontact other electrical terminals E8, the latter being supported by thecasing in a stationary manner. It is to be understood that the ring 66and its terminals 61 rotate with respect to the casing and, as is seenin Fig. 2, rotation thereof in the clockwise direction turns the lighton and rotation thereof in a counter-clockwise direction turns the lightoi. For maintaining the ring 66 in position, it is disposed sbetween anexterior flange 69 of the casing and a flange 1!) of the nut.

In order to present a zero point for the indicia 49 and in order tointerpolate between the marks of such indicia, there is supported by aninteriorly disposed ear 13 of the housing, as by a small screw or rivetor the like, a plate 'I4 presenting an arcuate inner edge adapted tomate with the outer edge of the plate 4I. This edge 15 is also disposedbetween the source of light and the screen and presents Vernier markings16. It will, of course, be understood that for the indicia 49 andmarkings 1E to create an image on the screen, such indicia and markingsmust either be more susceptible to penetration by light than the plates4| and 14, or the susceptibility may be reversed. I prefer, however, tomake the plates 4I and 14 relatively clear and transparent and theindicia and markings relatively opaque. Thus, not only is the amount oirelative movement between the elements l2 and i8 multiplied by a ratioof nve to one, but such increased movement is further greatly magnifiedby the image produced on the screen and a vernier, visible on thescreen, is provided for interpolating small increments of such movement.It will of course be understood that the markings 'it of the Verniercould be a permanent part of the screen in which event the plate '14would be completely eliminated.

For quickly measuring relatively large amounts of movement between theelements i2 and I8 without the necessity of the operators observing thenumber of rotations of the plate 4|, means may be provided formechanically counting the number of such rotations, but I prefer thatone of the elements I2 and IB be provided with an elongated graduatedscale disposed in the direction of relative movement and the other ofsuch elements I prefer to provide with a Zero point and Vernier marking.

In View of the foregoing it will be seen that in order to measure theamount of relative movement, one needs simply to note a reading on thescreen before the movement has occurred and again after it has occurred,the difference between such readings being the amount of relativemovement. All this is accomplished without any adjustment of themeasuring device because the housing i6 and the casing 54 are completelysealed in, the wiping means being noted, dust, grit and other foreignmatters are elimihated from the working surfaces of a device-constructedin accordance with my invention. .The housing I6 and the casing 54substantiallycompletely enclose the working element of my invention,leaving exposed only certain portions ofthe element I6. The originalmagnication of the relative movement being accomplished by means of whatis in effect a single, rigid member and the iinal magnification beingaccomplished by light, the presence of mechanical levers for magnicationpurposes is eliminated.

A modification of this preferred vform of myv invention is seen in Fig.3, wherein elements identical to those-above are described and areidentied by reference characters identical to those above employed. Inthis reference the shaft of the roller 25 carries a roller 85, which isapproximately five times the diameter of roller 25, and a roller 86 isin rolling contact with the roller 85, the shaft of the former carryingthe plate 4l. The roller 86 is one-fifth the diameter of the roller 85.From this it will be obvious that the ratio of movement between theelements 25 and 4l of the modification is considerably larger than isltrue of the preferred form of this invention. It will be understoodthat the source of light, the indicia, the Vernier, and the screen arethe same in both forms of my invention, only the diiferences beingillustrated. The finish of the rollers and 86 is similar to that abovedescribed with respect to the roller 25 of the preferred form of myinvention, such rollers being preferred over mechanical levers or gearsinasmuch as it is desired to eliminate all lost motion and backlash.

Other iorms may be employed embodying the features of my inventioninstead of the one herein explained, change being made in the form orconstruction, provided the elements stated by any of the followingclaims or the equivalent of such stated elements be employed.

I therefore particularly point out and distinctly claim as my invention:

1. In a device for measuring relative movement between two relativelymovable parts, a member carried by one of said parts and presenting astraight edge disposed in the direction of relative movement of saidparts, said member being movable with respect to said one part otherthan in said direction and immovable in said direction, a housingcarried by the other of said parts and having a pair of openings throughwhich said straight edge projects, a roller in said housing and adaptedto contact said straight edge, a disc carried by said housing andadapted for rolling against said member along a surface of the latterwhich is remote from said straight edge, a pair of springs interposedbetween said housing and the axis of said disc for urging said disctowards said member and consequently for urging said straight edgetowards said roller, said springs being disposed on opposite sides ofsaid disc, a circular plate actuated by said roller and having indiciaon the outer edge thereof, said indicia and said plate being ofcontrasting susceptibility to penetration by light, a source of lightfor projecting light rays on said outer edge whereby an image iscreated, a screen for receiving said image, and a lens interposedbetween said outer edge and said screen for magnifying said image, therebeing a Zero point for said indicia whereby movement by one of saidparts with respect to the other of said parts causes a change of imageon said screen and the amount of relative movement of said parts isreadily ascertainable.

2. In adevice adapted for measuring relative movement between two parts,transparent means including indicia responsive to relative movement ofsaid parts, a source of light for projecting the image of said indiciaon a screen, a screen for receiving said image, a, ring surrounding saidscreen," and electrical switching means responsive to movementrof saidring forrturning said `l() source of light on and off.

3."A pairof relatively movable 'Vpirts, a roller carried by one ofy saidparts', a rigidrmember pre JOSEPH VERDERBER.

